Objectives: This study examines the association between emotional support and tooth brushing according to family cohabitation in the socio ecological model. Methods: The study used data from face-to-face interviews of 719 adults aged 30-90 years, living in Gangwon State. The dependent variables were tooth brushing after lunch and dinner (including before going to bed). The independent variables were living conditions and emotional support. Multiple logistic regression analysis was conducted to confirm the association between emotional support and tooth brushing. Results: The results showed that 81.4% of people lived with their family, and 85.9% had family (friends) with whom they could share oral problems (p< 0.01). Among those living with their family, 82.3% (p >0.05) brushed after lunch and 81.9% (p>0.05) brushed after dinner. Tooth brushing after lunch was 1.5 times more likely among those who shared oral problems with their family (friends); however, this was not statistically significant (95% CI: 0.92-2.29). Tooth brushing after dinner was 1.0 times more likely among those who shared oral problems with their family (friends); however, this was not statistically significant (95% CI: 0.43-2.35). Conclusions: Emotional support may help to promote tooth brushing practice among adults.